1. Field of the Invention
The present invention relates generally to medical devices and more specifically to detection methods and systems for determining a fill status of a canister of fluid used with medical devices.
2. Description of Related Art
The treatment of open wounds and sores such as decubitis ulcers and those ulcers found on the feet of diabetics is problematic. Proper treatment of such wounds which are frequently infected with bacterial pathogens is multifactorial. Surgery is usually required to remove dead and necrotic tissue. Antibiotics are used to inhibit the growth or kill the pathogenic bacteria, if possible. At the same time, proper nutrition is necessary to maintain the health status of the patient and more importantly, proper wound care is essential to healing of the wound or sore.
Proper wound care requires keeping the wound clean and dry. When the wound is infected, the underlying tissue expresses serous fluids and possibly a purulent exudate, both of which have to be removed to promote wound healing. Traditional methods of removing the aforementioned fluids required a mechanical scrubbing of the wound and drying of the wound with sponges. This procedure is not only painful for the patient but also increases the possibility of superinfection of the wound by bacteria introduced into the wound during treatment.
An alternative to this mechanical scrubbing of the open wound is a negative pressure wound closure device. This negative pressure wound closure device consists of a foam pad which is placed over the wound to form a relatively air tight and leak proof seal around the wound. The negative pressure wound closure device also has a vacuum pump fluidly coupled to the pad which is seated over the patient's wound. When the vacuum pump is activated, a negative pressure is created inside the pad covering the wound. The fluids expressed by the wound are removed through the foam pad by the negative pressure and transported through a tube connecting the foam pad to a canister. The canister collects the fluids removed from the wound. When the canister is full of fluid removed from the wound, the canister is emptied and reengaged to the vacuum system. Attempts have been made to alert the user when the canister is full of wound fluid. These methods have been aimed at directly measuring the amount of wound fluid in the canister.
However, existing methods of directly measuring the amount of wound fluid in the canister have proved unreliable because, generally, the wound fluid is viscous. The fluid also frequently foams, bubbles, and traps air, which may result in the fluid not settling to the bottom of the canister. There remains a need in the art for a reliable system and method to alert the user when the canister for collection of wound fluid is full and in need of emptying.